1. Field of the Invention
The present invention relates to a memory system in which a nonvolatile semiconductor memory is mounted, and to a controller.
2. Description of the Related Art
In recent years, a memory system such as a memory card, which is one of removable memory devices, has widely been used in various types of portable electronic apparatuses such as a personal computer (PC), a PDA, a camera and a mobile phone. There is known a memory card in which a controller is not mounted and only a NAND-type flash memory is mounted. In this NAND-type flash memory, an erase block size is normally small and is set at, e.g., 16 Kbytes.
At present, a NAND-type flash memory, which is inexpensive and has a large capacity and a large erase block size, has begun to be used as a NAND-type flash memory which is mounted in a memory card. In this NAND-type flash memory, a controller is mounted and the erase block size is set at, e.g., 256 Kbytes.
In a shipment test of the memory card including the controller, it is necessary to individually test the controller and the nonvolatile semiconductor memory. There is known a pass-through mode in which the nonvolatile semiconductor memory is directly accessed without intervention of the controller, thereby to independently test the nonvolatile semiconductor memory. In order to realize the pass-through mode, a method has been proposed wherein a first operation mode and the pass-through mode are switched in accordance with a mode signal which is input from a mode terminal that is an external connection pin (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2004-158098).
In the above method in which the mode terminal is provided, however, the increase in number of external connection pins leads to an increase in size of the whole memory card and an increase in fabrication cost of the memory card. Moreover, the structure of a host device (tester), which tests the memory card, needs to be modified so as to adapt to the increase in number of external connection pins.